PERFORCE change 123099 for review
Brian Chu
chub at FreeBSD.org
Sun Jul 8 08:29:31 UTC 2007
http://perforce.freebsd.org/chv.cgi?CH=123099
Change 123099 by chub at chub-msdosfs on 2007/07/08 08:28:50
fsck_msdosfs's loading of the bootsector now uses the unified headers in fs/sys/msdosfs instead of hard coding offsets to variables.
Affected files ...
.. //depot/projects/soc2007/chub-msdosfs2/sbin/fsck_msdosfs/boot.c#2 edit
Differences ...
==== //depot/projects/soc2007/chub-msdosfs2/sbin/fsck_msdosfs/boot.c#2 (text+ko) ====
@@ -30,8 +30,8 @@
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+#include <sys/cdefs.h>
-#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: boot.c,v 1.9 2003/07/24 19:25:46 ws Exp $");
static const char rcsid[] =
@@ -44,131 +44,164 @@
#include <stdio.h>
#include <unistd.h>
+#include <fs/msdosfs/bootsect.h>
+#include <fs/msdosfs/bpb.h>
#include "ext.h"
#include "fsutil.h"
int
-readboot(dosfs, boot)
- int dosfs;
- struct bootblock *boot;
+readboot(int dosfs, struct bootblock *boot)
{
- u_char block[DOSBOOTBLOCKSIZE];
- u_char fsinfo[2 * DOSBOOTBLOCKSIZE];
- u_char backup[DOSBOOTBLOCKSIZE];
+ union bootsector buffer;
+ union bootsector backup;
+ struct byte_bpb50 *pfat50;
+ struct byte_bpb710 *pfat710;
+ struct byte_Extboot *pfatext;
+ struct fsinfo fsstruct;
int ret = FSOK;
- if (read(dosfs, block, sizeof block) < sizeof block) {
+ if (read(dosfs, &buffer, sizeof(union bootsector))
+ < sizeof(union bootsector)) {
perror("could not read boot block");
return FSFATAL;
}
- if (block[510] != 0x55 || block[511] != 0xaa) {
- pfatal("Invalid signature in boot block: %02x%02x", block[511], block[510]);
+ if (buffer.bs50.bsBootSectSig0 != BOOTSIG0 ||
+ buffer.bs50.bsBootSectSig1 != BOOTSIG1) {
+ pfatal("Invalid signature in boot block: %02x%02x",
+ buffer.bs50.bsBootSectSig1,
+ buffer.bs50.bsBootSectSig0);
return FSFATAL;
}
+
+ /* set the bpb structs to the boot sector's bpb */
+ pfat50 = (struct byte_bpb50 *)&buffer.bs50.bsBPB;
+ pfat710 = (struct byte_bpb710 *)&buffer.bs710.bsBPB;
- memset(boot, 0, sizeof *boot);
+ memset(boot, 0, sizeof(struct bootblock));
boot->ValidFat = -1;
- /* decode bios parameter block */
- boot->BytesPerSec = block[11] + (block[12] << 8);
- boot->SecPerClust = block[13];
- boot->ResSectors = block[14] + (block[15] << 8);
- boot->FATs = block[16];
- boot->RootDirEnts = block[17] + (block[18] << 8);
- boot->Sectors = block[19] + (block[20] << 8);
- boot->Media = block[21];
- boot->FATsmall = block[22] + (block[23] << 8);
- boot->SecPerTrack = block[24] + (block[25] << 8);
- boot->Heads = block[26] + (block[27] << 8);
- boot->HiddenSecs = block[28] + (block[29] << 8) + (block[30] << 16) + (block[31] << 24);
- boot->HugeSectors = block[32] + (block[33] << 8) + (block[34] << 16) + (block[35] << 24);
+ /* decode bios parameter block and store in a compacted
+ * architecture independent data structure for future use
+ */
+ boot->BytesPerSec = getushort(pfat50->bpbBytesPerSec);
+ boot->SecPerClust = pfat50->bpbSecPerClust;
+ boot->ResSectors = getushort(pfat50->bpbResSectors);
+ boot->FATs = pfat50->bpbFATs;
+ boot->RootDirEnts = getushort(pfat50->bpbRootDirEnts);
+ boot->Sectors = getushort(pfat50->bpbSectors);
+ boot->Media = pfat50->bpbMedia;
+ boot->SecPerTrack = getushort(pfat50->bpbSecPerTrack);
+ boot->Heads = getushort(pfat50->bpbHeads);
+ boot->HiddenSecs = getulong(pfat50->bpbHiddenSecs);
+ boot->HugeSectors = getulong(pfat50->bpbHugeSectors);
- boot->FATsecs = boot->FATsmall;
+ /* first defaulting to FAT12/FAT16 for number of FAT sectors */
+ boot->FATsecs = getushort(pfat50->bpbFATsecs);
- if (!boot->RootDirEnts)
+ if (boot->RootDirEnts == 0) {
+ /* FAT32 parsing */
boot->flags |= FAT32;
- if (boot->flags & FAT32) {
- boot->FATsecs = block[36] + (block[37] << 8)
- + (block[38] << 16) + (block[39] << 24);
- if (block[40] & 0x80)
- boot->ValidFat = block[40] & 0x0f;
+ boot->FATsecs = getulong(pfat710->bpbBigFATsecs);
+ if (pfat710->bpbExtFlags[0] & 0x80) {
+ boot->ValidFat = pfat710->bpbExtFlags[0] & 0x0f;
+ }
/* check version number: */
- if (block[42] || block[43]) {
- /* Correct? XXX */
+ if (pfat710->bpbFSVers[0] != 0 ||
+ pfat710->bpbFSVers[1] != 0) {
pfatal("Unknown file system version: %x.%x",
- block[43], block[42]);
+ pfat710->bpbFSVers[1],
+ pfat710->bpbFSVers[0]);
return FSFATAL;
}
- boot->RootCl = block[44] + (block[45] << 8)
- + (block[46] << 16) + (block[47] << 24);
- boot->FSInfo = block[48] + (block[49] << 8);
- boot->Backup = block[50] + (block[51] << 8);
+
+ boot->RootCl = getulong(pfat710->bpbRootClust);
+ boot->FSInfo = getushort(pfat710->bpbFSInfo);
+ boot->Backup = getushort(pfat710->bpbBackup);
if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
- != boot->FSInfo * boot->BytesPerSec
- || read(dosfs, fsinfo, sizeof fsinfo)
- != sizeof fsinfo) {
+ != boot->FSInfo * boot->BytesPerSec) {
+ perror("could not seek to fsinfo block to read");
+ return FSFATAL;
+ }
+
+ if (read(dosfs, &fsstruct, sizeof(struct fsinfo))
+ != sizeof(struct fsinfo)) {
perror("could not read fsinfo block");
return FSFATAL;
}
- if (memcmp(fsinfo, "RRaA", 4)
- || memcmp(fsinfo + 0x1e4, "rrAa", 4)
- || fsinfo[0x1fc]
- || fsinfo[0x1fd]
- || fsinfo[0x1fe] != 0x55
- || fsinfo[0x1ff] != 0xaa
- || fsinfo[0x3fc]
- || fsinfo[0x3fd]
- || fsinfo[0x3fe] != 0x55
- || fsinfo[0x3ff] != 0xaa) {
+
+ if (memcmp(fsstruct.fsisig1, "RRaA", 4) ||
+ memcmp(fsstruct.fsisig2, "rrAa", 4) ||
+ memcmp(fsstruct.fsisig3, "\0\0\125\252", 4) ||
+ memcmp(fsstruct.fsisig4, "\0\0\125\252", 4)) {
pwarn("Invalid signature in fsinfo block");
+
if (ask(0, "fix")) {
- memcpy(fsinfo, "RRaA", 4);
- memcpy(fsinfo + 0x1e4, "rrAa", 4);
- fsinfo[0x1fc] = fsinfo[0x1fd] = 0;
- fsinfo[0x1fe] = 0x55;
- fsinfo[0x1ff] = 0xaa;
- fsinfo[0x3fc] = fsinfo[0x3fd] = 0;
- fsinfo[0x3fe] = 0x55;
- fsinfo[0x3ff] = 0xaa;
+ memcpy(fsstruct.fsisig1, "RRaA", 4);
+ memcpy(fsstruct.fsisig2, "rrAa", 4);
+ memcpy(fsstruct.fsisig3, "\0\0\125\252", 4);
+ memcpy(fsstruct.fsisig4, "\0\0\125\252", 4);
+
if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
- != boot->FSInfo * boot->BytesPerSec
- || write(dosfs, fsinfo, sizeof fsinfo)
- != sizeof fsinfo) {
- perror("Unable to write FSInfo");
+ != boot->FSInfo * boot->BytesPerSec) {
+ perror("could not seek to fsinfo block to fix/write");
+ return FSFATAL;
+ }
+
+ if (write(dosfs, &fsstruct, sizeof(struct fsinfo))
+ != sizeof(struct fsinfo)) {
+ perror("could not write fixed fsinfo");
return FSFATAL;
}
+
ret = FSBOOTMOD;
- } else
+ }
+ else {
+ /* we didn't fix the corrupted FSInfo block */
boot->FSInfo = 0;
+ }
}
- if (boot->FSInfo) {
- boot->FSFree = fsinfo[0x1e8] + (fsinfo[0x1e9] << 8)
- + (fsinfo[0x1ea] << 16)
- + (fsinfo[0x1eb] << 24);
- boot->FSNext = fsinfo[0x1ec] + (fsinfo[0x1ed] << 8)
- + (fsinfo[0x1ee] << 16)
- + (fsinfo[0x1ef] << 24);
+
+ if (boot->FSInfo != 0) {
+ boot->FSFree = getulong(fsstruct.fsinfree);
+ boot->FSNext = getulong(fsstruct.fsinxtfree);
}
if (lseek(dosfs, boot->Backup * boot->BytesPerSec, SEEK_SET)
- != boot->Backup * boot->BytesPerSec
- || read(dosfs, backup, sizeof backup) != sizeof backup) {
+ != boot->Backup * boot->BytesPerSec) {
+ perror("could not seek to read backup bootblock");
+ return FSFATAL;
+ }
+
+ if (read(dosfs, &backup, sizeof(union bootsector))
+ != sizeof(union bootsector)) {
perror("could not read backup bootblock");
return FSFATAL;
}
- backup[65] = block[65]; /* XXX */
- if (memcmp(block + 11, backup + 11, 79)) {
- /* Correct? XXX */
+
+ // never written back to disk
+ //backup.bs710.bsExt.exReserved1 = buffer.bs710.bsExt.exReserved1;
+
+ if (memcmp(buffer.bs710.bsBPB,
+ backup.bs710.bsBPB,
+ sizeof(struct bpb710)) ||
+ memcmp(buffer.bs710.bsExt,
+ backup.bs710.bsExt,
+ sizeof(struct extboot))) {
+
pfatal("backup doesn't compare to primary bootblock");
if (alwaysno)
pfatal("\n");
else
return FSFATAL;
}
- /* Check backup FSInfo? XXX */
+
+ /* Unnecessary to check the backup FSInfo because there isn't
+ * an physical backup copy of the FSInfo block. There's only a
+ * backup of the FSInfo block number, which was checked (bsBPB) above.
+ */
}
boot->ClusterOffset = (boot->RootDirEnts * 32 + boot->BytesPerSec - 1)
@@ -190,13 +223,14 @@
boot->NumSectors = boot->Sectors;
} else
boot->NumSectors = boot->HugeSectors;
- boot->NumClusters = (boot->NumSectors - boot->ClusterOffset) / boot->SecPerClust;
+ boot->NumClusters = (boot->NumSectors - boot->ClusterOffset)
+ / boot->SecPerClust;
- if (boot->flags&FAT32)
+ if (boot->flags & FAT32)
boot->ClustMask = CLUST32_MASK;
- else if (boot->NumClusters < (CLUST_RSRVD&CLUST12_MASK))
+ else if (boot->NumClusters < (CLUST_RSRVD & CLUST12_MASK))
boot->ClustMask = CLUST12_MASK;
- else if (boot->NumClusters < (CLUST_RSRVD&CLUST16_MASK))
+ else if (boot->NumClusters < (CLUST_RSRVD & CLUST16_MASK))
boot->ClustMask = CLUST16_MASK;
else {
pfatal("Filesystem too big (%u clusters) for non-FAT32 partition",
@@ -230,33 +264,38 @@
}
int
-writefsinfo(dosfs, boot)
- int dosfs;
- struct bootblock *boot;
+writefsinfo(int dosfs, struct bootblock *boot)
{
+ struct fsinfo fsstruct;
u_char fsinfo[2 * DOSBOOTBLOCKSIZE];
- if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
- != boot->FSInfo * boot->BytesPerSec
- || read(dosfs, fsinfo, sizeof fsinfo) != sizeof fsinfo) {
- perror("could not read fsinfo block");
+ if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
+ != boot->FSInfo * boot->BytesPerSec) {
+ perror("could not seek to fsinfo block to read");
+ return FSFATAL;
+ }
+
+ if (read(dosfs, &fsstruct, sizeof(struct fsinfo))
+ != sizeof(struct fsinfo)) {
+ perror("could not read fsinfo block");
+ return FSFATAL;
+ }
+
+ putulong(&fsstruct.fsinfree, boot->FSFree);
+ putulong(&fsstruct.fsinxtfree, boot->FSNext);
+
+ if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
+ != boot->FSInfo * boot->BytesPerSec) {
+ perror("could not seek to fsinfo block to write new block");
+ return FSFATAL;
+ }
+
+ if (write(dosfs, &fsstruct, sizeof(struct fsinfo))
+ != sizeof(struct fsinfo)) {
+ perror("could not write fixed fsinfo");
return FSFATAL;
}
- fsinfo[0x1e8] = (u_char)boot->FSFree;
- fsinfo[0x1e9] = (u_char)(boot->FSFree >> 8);
- fsinfo[0x1ea] = (u_char)(boot->FSFree >> 16);
- fsinfo[0x1eb] = (u_char)(boot->FSFree >> 24);
- fsinfo[0x1ec] = (u_char)boot->FSNext;
- fsinfo[0x1ed] = (u_char)(boot->FSNext >> 8);
- fsinfo[0x1ee] = (u_char)(boot->FSNext >> 16);
- fsinfo[0x1ef] = (u_char)(boot->FSNext >> 24);
- if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
- != boot->FSInfo * boot->BytesPerSec
- || write(dosfs, fsinfo, sizeof fsinfo)
- != sizeof fsinfo) {
- perror("Unable to write FSInfo");
- return FSFATAL;
- }
+
/*
* Technically, we should return FSBOOTMOD here.
*
@@ -264,7 +303,7 @@
* support for FAT32) doesn't maintain the FSINFO block
* correctly, it has to be fixed pretty often.
*
- * Therefor, we handle the FSINFO block only informally,
+ * Therefore, we handle the FSINFO block only informally,
* fixing it if necessary, but otherwise ignoring the
* fact that it was incorrect.
*/
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